Hypertext transfer protocol (HTTP) is an application-layer protocol in a Transmission Control Protocol/Internet Protocol (TCP/IP) model. When a client computing device and a server need to communicate with each other, a TCP connection is established first between the client computing device and the server, and the client-device sends HTTP requests (for example, using a browser-type program) to the server.
HTTP requests can be used to send monitoring data recorded by the client computing device to the server. When a user of and client computing device performs an operation on a web page in a browser (for example, clicking a link on the web page or logging in to an account), the client computing device can monitor the operation and send the monitoring data to a server using an HTTP request.
After receiving the HTTP request, the server can return a response to the client computing device. A normal response can indicate that the HTTP request is successfully sent. An abnormal/unexpected response or lack of a response can indicate that the HTTP request failed to be sent and the server does not receive the data. For example, when a web page redirects, that is, a first web page is redirected to a second web page, the client computing device can offload the content of the first web page and load the content of the second web page. During the offloading process, the HTTP request may fail to be sent or cancelled by the browser. In such case, the server may not receive the monitoring data, which can result in data loss.